生物炭对塿土土壤温室气体及土壤理化性质的影响

通过田间小区试验,分别向塿土土壤中添加0、20、40、60、80 t·hm~(-2)的苹果果树枝条生物炭后,分析了生物炭对土壤温度、土壤团聚体、NO_3~--N、NH_4~+-N、微生物量碳以及土壤温室气体排放的影响.结果表明,生物炭可以缓解土壤温度的变化,增加土壤大团聚体的数量,尤其是5 mm、5~2 mm和1~0.5 mm的团聚体数量.与对照相比,随着生物炭施用量的增加,土壤NO_3~--N、NH_4~+-N、微生物量碳分别增加了4.9%~33.9%、9.1%~41.1%和11.8%~38.5%.本研究中生物炭对土壤温室气排放的影响主要表现为:添加生物炭后,土壤CO_2的排放量以及CH_4的吸收汇分别增加了6.73%~23.35%和3.62%~14.17%;施用20 t·hm~(-2)和40 t·hm~(-2)的生物炭降低了土壤N_2O的排放和综合增温潜势(GWP),而当生物炭施用量大于等于60 t·hm~(-2)时反而增加了土壤N_2O的排放和综合增温潜势(GWP).说明生物炭作为一种土壤改良剂和碳减排剂,能够改善土壤质量,提高土壤肥力,提高农田土壤增汇减排的作用,此外,选择合适的生物炭施用量至关重要.

Influence of Biochar on Greenhouse Gases Emissions and Physico-chemical Properties of Loess Soil

Biochar is known to be a good soil amendment to improve soil physical and biochemical characteristics, to increase crop yield, and to mitigate greenhouse gas emissions from soils. In this study, five addition levels of apple tree branches-derived biochar (0, 20, 40, 60, 80 t·hm^-2) were used in field plot test. The effects of biochar on soil temperature, soil aggregates, NO₃^--N, NH₄⁺-N, microbial biomass carbon and greenhouse gas fluxes were investigated during the whole pepper growth season. The results showed that biochar amendment increased the temperature moderation capability of soil and increased the content of soil macro-aggregates, especially the content of aggregates with sizes >5 mm, 5-2 mm and 1-0.5 mm. As compared with the control, the contents of NO₃^--N, NH₄⁺-N and microbial biomass carbon increased by 4.9%-33.9%, 9.1%-41.1% and 11.8%-38.5% with the increase of biochar content respectively. Biochar amendment increased CO₂ emissions and CH₄ uptake by 6.73%-23.35% and 3.62%-14.17%, respectively. N₂O emissions and global warming potential (GWP) decreased at biochar levels of 20 and 40 t·hm^-2 and increased when the biochar levels were 60 and 80 t·hm^-2 as compared with the control. The results suggested that as a soil conditioner, biochar improved soil quality, soil fertility and function of agriculture soil on carbon sequestion and decreased emission cut. In addition, the choice of biochar level is very important.